1. Field of the Invention
This invention relates to a semiconductor manufacturing unit and a semiconductor manufacturing method for conducting a thermal process to a semiconductor substrate such as a semiconductor wafer.
2. Disclosure of the Prior Art
As a conventional semiconductor-manufacturing unit, there is known a vertical thermal processing unit which can conduct a process to a plurality of semiconductor wafers at one time. In such a unit, the plurality of the semiconductor wafers are held in a tier-like manner by a wafer holder, which is called a wafer-boat. After that, the wafer holder is conveyed into a vertical thermal processing furnace, which has a heater such as a resistance heater, through a lower portion thereof. Then, an atmosphere in the furnace is heated to a predetermined temperature in order to conduct a thermal process to the plurality of semiconductor wafers. The thermal process may be, for example, a CVD process, a diversion process, an oxidation process, or the like. In a CVD process, the atmosphere in the vertical thermal processing furnace is heated up to, for example about 500-800xc2x0 C. In a diversion process or an oxidation process, the atmosphere in the vertical thermal processing furnace is heated up to, for example more than 800xc2x0 C.
Thus, a thermal process to the wafers is conducted at a high temperature. In general, residual heat is exhausted through a wall surrounding the vertical thermal processing furnace and/or a duct provided at a loading chamber of the wafer boat. Alternatively, residual heat is forcibly collected by a cooling medium such as a cooling water flowing through a cooling pass provided around the vertical thermal processing furnace, and the collected heat is disposed.
As described above, energy of the residual heat produced in the thermal process to the wafers has been disposed in vain. In addition, there has been a problem that exhausting or collecting (cooling) the residual heat as described above requires large electric power involving a high cost. Especially, when a wafer has a size of 300 mm, a heater for heating the wafer has to be large correspondingly to the size of the wafer. In the case, energy of residual heat is liable to be larger. Thus, disposed energy of the heat is also liable to be larger, which makes worse an energy efficiency of a semiconductor manufacturing plant.
This invention is intended to solve the above problem effectively. The object of this invention is to provide a semiconductor manufacturing unit which can be used with a high energy efficiency.
In order to achieve the object, a semiconductor manufacturing unit according to the invention is characterized by comprising: a processing container into which a semiconductor substrate is adapted to be conveyed; a heating unit for heating an atmosphere in the processing container in order to thermally process the semiconductor substrate; and a plane thermoelectric module having a first surface arranged opposite to an area heated by the heating unit for converting a thermal energy of the area into an electric energy by making use of Seebeck effect.
According to the feature, since the thermal energy which has been disposed in conventional units can be used as the electric energy, total energy efficiency of the semiconductor manufacturing unit can be raised.
Preferably, the plane thermoelectric module has a second surface, and a cooling unit is provided in the second surface in order to improve an efficiency of the Seebeck effect.
Preferably, an insulating material is arranged between the area heated by the heating unit and the thermoelectric module.
Preferably, the thermoelectric module is connected to a rechargeable battery. For example, the rechargeable battery may be adapted to function as a backup power source for the semiconductor manufacturing unit.
Preferably, the area heated by the heating unit is formed in such a manner that the area surrounds the processing container. In the case, the thermoelectric module may be arranged in such a manner that the thermoelectric module surrounds the area heated by the heating unit and that the first surface of the thermoelectric module is opposite to an outside of the area.
Preferably, the container is formed in such a manner that a substrate holder for holding a plurality of semiconductor substrate in a tier-like manner can be conveyed into the container.
Preferably, the substrate holder is adapted to wait at a waiting position when the substrate holder is taken out from the container, and a second thermoelectric module is arranged around the waiting position in such a manner that a first surface of the second thermoelectric module is opposite to the waiting position.
In the case, preferably, the second thermoelectric module has a second surface, and a cooling unit is provided in the second surface in order to improve an efficiency of Seebeck effect. Further preferably, the second thermoelectric module is connected to a rechargeable battery. The rechargeable battery may also be adapted to function as a backup power source for the semiconductor manufacturing unit.
In addition, a semiconductor manufacturing method according to the invention is a method of using a semiconductor processing unit including: a processing container into which a semiconductor substrate is adapted to be conveyed; a heating unit for heating an atmosphere in the processing container in order to thermally process the semiconductor substrate; and a plane thermoelectric module having a first surface arranged opposite to an area heated by the heating unit for converting a thermal energy of the area into an electric energy by making use of Seebeck effect; comprising: a step of conveying the semiconductor substrate into the container; a step of thermally processing the semiconductor substrate in the container by means of the heating unit; and a step of converting the thermal energy of the area heated by the heating unit into the electric energy by means of the thermoelectric module.
Preferably, the plane thermoelectric module of the semiconductor manufacturing unit has a second surface, a cooling unit is provided in the second surface in order to improve an efficiency of the Seebeck effect, and the method further comprises a step of cooling the second surface of the thermoelectric module by means of the cooling unit.
In addition, preferably, the thermoelectric module of the semiconductor manufacturing unit is connected to a rechargeable battery, and the method further comprises a step of charging the rechargeable battery with the electric energy converted by the thermoelectric module.